Conventional sliding bearings generally have rather short service life due to the wear to which they are subjected, especially at start and stop.
Magnetic sliding bearings in recent times have had an ever increasing importance and are used in many applications, e.g. at disk storage for computers, in domestic machines and in other applications , where it is aimed at silent operation, extended operation life and high rotational accuracy. An important advantage at such bearings is that the lubricant, which contains particles of magnetizable material, is retained in the bearing by means of the magnetic field generated by the magnetic bearing sleeve, whereby leakage of the lubricant is prevented. Such a magnetic fluid, also referred to as "ferro-fluid", consists of a colloidal dispersion or suspension of small magnetic particles in a carrier fluid, e.g. oil. The magnetic particles are retained in stable colloidal suspension by means of a dispersant. Such magnetic fluids can be positioned and retained in spaces without use of a container by means of a magnetic field.
SUMMARY OF THE INVENTION
The purpose of the present invention is to provide a sliding bearing of the type initially mentioned, which gives a hydrodynamic as well as a hydrostatic lubrication without use of oil pump or the like and which has a long service life. According to the invention this has been achieved therein that the sliding bearing has sliding shoes adapted at rotation of the shaft to cause a compression of the fluid volume and to urge fluid to pass out under the sliding shoe at the same time as the hydrostatic pressure increases in the spaces between the sliding shoes.